Electric circuit breaker



J. KOPELlOWlTSCH 1,935,228

ELECTRIC CIRCUIT BREAKER Nov. 14, 1933.

Filed Dec. '7, 1931 Patented Nov. 14, 1933 ELECTRIC CIRCUIT BREAKERJakob Kopeliowitsch, Baden, Switzerland, as-

signor to Aktiengesellschaft Brown Boveri & Cie., Baden, Switzerland, ajoint-stock company of Switzerland Application December '7, 1931, SerialNo. 579,524, and in Germany December 6, 1930 6 Claims.

This invention relates to improvements in electric circuit breakers andlead-in bushings and more particularly to circuit breakers in which thecontacts interrupting the circuit are separated in a vacuum withincasings formed of insulating material which are adapted for use asbushings for the terminals of high' potential apparatus.

When circuit breakers; employing an interposed non-conductive fluid,such as oil, to aid in quenching the arc established upon separation ofthe contacts to interrupt an electric circuit; are used in high voltagelines the dimensions of a circuit breaker-having sufficient capacity tointerrupt short circuits become so large that the circuit breakerbecomes very expensive and requires a large space. Due to the large sizeof such circuit breakers, it is impossible to mount the circuit breakersupon the tanks of high volt- IO age apparatus such as transformers oreven closely adjacent such tanks. Such circuit breakers also have otherwell known disadvantages which those skilled in the art have attemptedto avoid by the use of circuit breakers without oil such as a circuitbreaker in which the circuit is interrupted in a vacuum.

The difficulties in the construction and operation of circuit breakersoperating in a vacuum and of such size that the structure may be used asa lead-in bushing are to be found not only in the maintenance of thevacuum at the desired value due to the continuous liberation of occludedgases from the materials of which the evacuated chamber is constructedbut also in the difliculty of constructing a vacuum chamber ofinsulating material of suflicient size which will be gas-tight.

Ceramic materials are usually used for the insulation of conductors athigh voltages and it is necessary that the dimensions of a vacuumchamber for high voltages formed of such materials be such that theexposed surfaces will prevent flash-overs or glow discharges. It is,however, very difiicult to construct a chamber of ceramic materials ofsufficient size in such manner that the chamber will be continuouslygas-tight and will therefore be capable of being maintained at asuitable vacuum. It is therefore among the objects of the presentinvention to provide an electric circuit breaker in which contacts areseparated within a vacuum maintained within an integral chamber ofinsulating material.

Another object of the invention is to provide a circuit breakeroperating in an evacuated cham ber of such size that the chamber may bemade integrally from ceramic materials.

discharges therefrom.

Another object of the invention is to provide a combined circuit breakerand terminal bushing for high voltage apparatus in which the contactsinterrupting the circuit are operated in an evacuated chamber which isarranged within an insulating casing in which the space between theevacuated chamber and the casing is filled with an insulating fluid andin which means are provided within the casing to secure potentialdistribution over the entire surface of the casing.

Objects and advantages other than those above set forth will be apparentfrom the following description when read in connection with theaccompanying drawing forming a portion of the disclosure of the presentinvention which is a vertical sectional View illustrating one embodimentof the invention, in which a pair of contacts operate within anevacuated chamber which is arranged within an insulating casing filledwith a suitable dielectric and provided with means to increase theflash-over voltages, and to secure potential distribution over thesurface of the easing to obtain a structure operating as a circuitbreaker and also adapted for use as a terminal bushing for highpotential apparatus.

Referring more particularly to the drawing by characters of reference,the reference numeral 1 designates a gas-tight chamber of insulatingmaterial, such as a ceramic material, formed with a materially decreasedcentral section for a purpose which will appear hereinafter.

The outer ture.

The conductor 4-. is connected at the end thereof within the chamber 1with one end of a flexible conductor 6.

The other end of the flexible conductor is connected with one end of arod 7 forming a contact movable into and out of contact with the fixedcontact 3.

Contact '7 is operated into and out of connection with contact 3 by theaction of coils B or 9 which are arranged about the decreased centralsection of the chamber 1 and act upon an enlarged portion 11 on themovable contact which enlarged portion serves as the armature of asolenoid formed by the coils 8, 9. The coil 9, upon energization thereoffrom a suitable source (not shown), causes upward or circuit closingmovement of contact 7 and the coil 8 causes downward or circuit openingmovement of contact Movement of contact '7 is guided by walls 12'' and13 extending across the chamber 1, Such walls may be made integral withthe chamber or may be separate therefrom and attached thereto asdesired. Chamber 1 is evacuated by a suitable evacuat ing pump (notshown) through a tubular connection 16 between the chamber and the pump.

The chamber 1 and its contacts are enclosed within a casing or housing,the greater portion of which is formed by an upper and a lowerinsulating portion 18 and 19, respectively. The insulators l8 and 19 arepreferably in the of hollow substantially conical members such as arenow used for the construction of oil filled bushings. The insulators arepreferably skirted as shown to increase the flash over distance and toprevent the occurrence of glow discharges, and are joined at the basesthereof by means of a flanged connecting member 21 into which the openbase ends of the insulators are sealed in fluidtight relation. The openends of the insulators are closed in fiuid-tight relation by means ofsimilar top and bottom closures 23 and 24 through which conductors 3-and4 extend and to which the conductors are secured. The end closures thusserve as terminals for the circuit to be controlled. The entire switchstructure including the chamber 1 and the contacts 3 and 7 is thusenclosed within a fluid-tight casing formed substantially of insulatingmaterial which casing is filled with an insulating liquid or gas and forwhich the upper closure 23 forms an expansion chamber. subjecting andmaintaining the insulating fluid under pressure further increases theflash-over voltages of the entire structure.

It is desirable to control the potential distribution over the exteriorsurface of the casing which result is accomplished by the arrangement ofa plurality of conductive cylinders 26 of different lengths about theevacuated chamber 1 and with in the casing l8, 19. The cylinders 26 arespaced from the chamber, from the casing and from each other and thespaces are filled with the insulating fluid filling the casing. Thecylinders are preferably embedded within insulation and thus formcondenser layers which create a uniform potential gradient over theentire surfaces of the easmg.

A circuit breaker such as disclosed may be operatively mounted either inthe vertical position shown or in a horizontal position and may beemployed for either indoor or out of door use. If desired the casingshown may be replaced by an integral casing of insulating material andthe circuit breaker may then serve as the terminal of high voltageapparatus such as transformer.

Due to the construction of the casing substantially of insulatingmaterial, the circuit breaker is especially adapted for mounting uponthe tanks of high potential apparatus such as transformers therebyeliminating the necessity for special terminal bushings for suchtransformers.

.zllthougli but one embodiment of the present invention has beenillustrated and described it incense will be apparent to those skilledin the art that various changes and modifications may be made thereinwithout departing from the spirit of the invention or from the scope orthe appended claims.

The invention claimed i. In combination, an oil-iilled lead-in bushingcomprising a pair of hollow "ating members with a flanged supportingring 11 posed therebetween and secured thereto, and a vacuum switchwithin said lead-in bushing comprising an evacuated casing supportedfrom said flanged supporting ring, and a pair of relatively movablecontacts within said evacuated casing and supported thereby, said vacuumswitch also comprising means ior clectromagnetically operating saidrelatively movable contacts.

2. In combination, an oil-filled lead-in bushing comprising a pair oi?hollow ins ing members with a flanged supporting ring erposedtherebetween and secured thereto, vacuum switch within said lead-inbushing comprising an evacuated casing supported from said flangedsupporting ring, and a pair of relatively movable contacts within saidevacuated casing and supported thereby, said vacuum switch alsocomprising means for electromagnetically operating said relativelymovable contacts, and. a potential distributing shield of conductivematerial supported from said flanged supporting ring and interposed inspaced relation between said flanged supporting ring and said evacuatedcontainer.

3. In combination with an oil-filled lead-in bushing comprising a pairof hollow insulating members with a metal supporting ring inteiposedtherebetween and a pair of terminal caps covering the remote ends ofsaid insulating members, of a vacuum switch within said lead-in bushingcomprising a three part evacuated container supported from said metalsupporting ring in spaced relation thereto, the middle section of saidevacuated container having an annular reduced portion, a pair ofrelatively movable contact memhere within said evacuated container andsupported from the end sections of said evacuated containerrespectively, said vacuum switch also cornprising a switch operatingwinding surrounding said annularly reduced portion.

4. In a combined circuit breaker and lead-in bushing, a metal mountingring, a pair of hollow insulating members extending in oppositedirections from said mounting ring and secured thereto, a pair ofbushing terminal members secured to the remote ends of said hollowinsulating members, a body of insulating liquid within said hollowinsulating members, an evacuated casing of insulating material immersedin said liquid and supported from said mounting ring in spaced relationthereto, said evacuated casing having an annular constricted portion, apair of relatively movable contact mem-- bers arranged within saidevacuated casing, and. electrically connected with said bushing terminalmembers respectively, and solenoid winding ar ranged in said annularconstricted portion and operable upon energization thereof to relativelymove said contact members.

5. In a combined circuit breaker and lead-in bushing, a flanged mountingring of metal, a pair of hollow insulating sleeves extending in oppositedirections from said flanged mounting ring and secured thereto, a pairof bushing terminal members covering the remote ends of said insulatingsleeves, a body of insulating liquid within said hollow umulatingsleeves, an evacuated container of insulating material immersed in saidliquid and supported from said flanged mounting ring in spaced relationthereto, a fixed contact arranged within said evacuated container andelectrically connected to one of said bushing terminal members, amovable contact arranged within said evacuated container andelectrically connected to the other of said bushing terminal members, amagnetic core member within said evacuated container operativelyconnected to said movable contact, a solenoid surrounding a portion ofsaid evacuated container adjacent said magnetic core member, andsolenoid energizing conductors extending from said solenoid through saidflanged mounting ring.

6. In combination, a supporting member having a hole therein, aconnecting member arranged coaxially of said hole and detachably securedto said supporting member, a pair of hollow conical shaped insulatingmembers extending in opposite directions from said connecting membersand secured thereto, a pair of terminal devices secured U to the remoteends of said insulating members, an

evacuated container of insulating material arranged coaxial of saidconical insulatingmembers and secured to said connecting member, an

evacuating conduit supported by said connecting member and incommunication with the interior of said evacuated container, a body ofinsulating liquid within said hollow insulating members and completelysurrounding said evacuated container, stationary and movable contactmembers arranged within said evacuated container and electricallyconnected with said terminal devices respectively, solenoid means foroperating said movable contact, and a plurality of conductors extendingfrom said solenoid means through said connecting member.

JAKOB KOPELIOWITSCH.

